Preheat oven to 165 degrees C. Grease a baking tray or line with baking paper.
In a large bowl cream together butter and sugar until fluffy. Mix in eggs, vanilla and amaretto. In a separate bowl mix flour, baking powder and salt. Stir flour mixture into butter mixture. Fold in nuts and white chocolate chips.
Divide dough into 4 equal parts. Place each 1/4 of dough on baking tray and form into logs about 35cm long and 4cm wide.
Bake 25 minutes in the preheated oven until very lightly brown. Cool and cut diagonally into 1cm slices. Arrange slices on baking tray and continue baking 8 minutes, until golden brown.
Amaretto is an Italian sweet almond-flavoured liqueur. It is made from a base of apricot and/or almond stones.